In my understanding, parcels up to $800 are still excempt
-
Welcome to ASR. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!
Thanks for testing. So the < 0.01% THD spec was accurate. I asked O-Noorus about that because it seems awfully high for PFFB, and they said they'd check. You confirmed that, so I wonder why it is so high. For the D1, there are some measurements here on ASR that place the highest harmonic at -106 dB which is very good though not quite Topping and 3e territory. The D1 has the same < 0.01% spec, btw.
www.audiosciencereview.com
I assume all your measurements except for those of the tone controls were in bypass mode? Then it is hard to understand how they can be so much worse than the D1's which I understand has the same tone / volume chip.
Could you please add a measurement of FR with 8 vs 4 R or any load vs. no load? That would tell us if it really uses PFFB.
The atrocios DAC behavior is another thing. The ESS 9023 is a solid DAC, - 70 dB is something I've only seen in those cheap optical to analog converters for $4. The only thing I can imagine is that the DAC and the TPA PFFB implementation are fine and something is seriously wrong with the tone control / preamp implementation.
O-Noorus D1 [TPA3255 PFFB] Stereo Amplifier - User Impressions | Owner's Thread
Wonder if there's a signal sensing auto-on/off function when used as a power amp (BP mode). There is no auto-ON/Off signal sensing feature for the amplifier, auto-ON/OFF is there only for screen display
www.audiosciencereview.com
I assume all your measurements except for those of the tone controls were in bypass mode? Then it is hard to understand how they can be so much worse than the D1's which I understand has the same tone / volume chip.
Could you please add a measurement of FR with 8 vs 4 R or any load vs. no load? That would tell us if it really uses PFFB.
The atrocios DAC behavior is another thing. The ESS 9023 is a solid DAC, - 70 dB is something I've only seen in those cheap optical to analog converters for $4. The only thing I can imagine is that the DAC and the TPA PFFB implementation are fine and something is seriously wrong with the tone control / preamp implementation.
Last edited:
Basically I agree that something strange is going on in the preamp section. But why would it treat the signal from the DAC even worse than from the RCA?
That is also my concern. DAC performance is degraded maybe due to bad circuit design or wrong value capacitors /resistors in the signal path.
i also have a very cheap TPA3255 generic amp board which is purchased from Ali. That small board is outperforming this D4 amp at 4 times less cost of this amplifier.
This thing is driving me crazy that something major is wrong in implementation of this amplifier.
Last edited:
Yeah, I've posted before that the Douk A5 and the Wiim Amp Pro, both with PFFB, barely outperform the Aiyima A-07 without PFFB at 1 kHz and are actually worse at higher frequencies, but this one here is firmly in the range of the poorer non-PFFB implemantations, meaning a good non-PFFB will run circles around it.
This is not to take away that the D4 will come in handy to play TV sound and - 70 dB HHD don't really matter in that application.
This is not to take away that the D4 will come in handy to play TV sound and - 70 dB HHD don't really matter in that application.
Agreed.
For me,.. from now on PFFB does not matter and is a waste of money. Since subjectively non-pffb amplifiers are sounding better to my ears.
Just buy any lowest price TPA3255 amplifier and connect it to high quality DAC and you're good to go.
Not necessarily. Poor PCB layout and poor output coils can make for an extremely poor non-PFFB and a mediocre PFFB amp. Good layout and good coils = A-07 or Wiim Amp, HHD - 90 dB, which is usually non-audible, especially when HHD is 2nd harmonic.
PFFB can be in ncore / purifi territory when excellent layout, very good coils and a loop design better than the white paper published by TI are used.
PFFB can be in ncore / purifi territory when excellent layout, very good coils and a loop design better than the white paper published by TI are used.
DoctorRobert
Member
- Joined
- Jul 22, 2020
- Messages
- 49
- Likes
- 87
I think the this a capable little amp with a relatively unique feature in the form of a defeatable tone control. If I was in the market for a desktop amp, I would consider it for this. I think SINAD has become overvalued on this site. Amir uses SINAD as a metric for 'engineering quality', to rate electronic components. That is a rational choice (I don't have a better alternative), but for me a buying decision is first and foremost driven by features. I love tone controls (I think they are underrated), to match less than perfect program material to my listining condition. I don't think I hear SINAD differences over 60dB (on speakers).
I love this site because it shows where your money buys you meaningful performance, but SINAD is just another metric.
I love this site because it shows where your money buys you meaningful performance, but SINAD is just another metric.
Although SINAD is not very good, according to the feedback from 90% of users, D4 sounds excellent and has strong musicality.
daniboun
Major Contributor
Could you please share link ? I guess you got measurements to attest ?
daniboun
Major Contributor
The PFFB essentially has the role of reducing load dependency... there is a plethora of TP325X on offer and you only have to look at the Sylph test in 2021 to realize that this D4 has a design problem
JL ELectronics Sylph-D200 Amplifier Module Review
This is a review and detailed measurements of the JL Electronic's (JLE) Sylph-D200 stereo amplifier module built on top of TI's TPA3255 amplifier IC. Depending on the configuration you pick, the module costs US $130 to $170. You can read more about it here...
audiosciencereview.com
daniboun
Major Contributor
Beware of confirmation bias) ASR is intended to be neutral by definition. Musicality is a purely subjective notion.
daniboun
Major Contributor
The brand nnew A5 pro from Douk includes now a tone control / well done PFFB with almost no load dependecy @ $ 99
Douk Audio A5 PRO TPA3255 Bluetooth Amplifier HiFi Class D Stereo Audio Amp
Features Upgraded Features for Versatile Use: The A5 PRO builds on the strengths of the A5, featuring upgraded Bluetooth 5.1 connectivity with a reset button, bass and treble knobs for precise tone adjustments, and a headphone output. It delivers clear, powerful audio, perfect for diverse uses...
doukaudio.com
daniboun
Major Contributor
Measurements ? since you said "That small board is outperforming this D4 amp at 4 times less cost of this amplifier."
daniboun
Major Contributor
How do you measure sound quality in a non-subjective way?
ICIETDIYEUR
Senior Member
Hello Dany 
Everyone seems to agree that the measurements on current devices are no longer audible.
Can we still talk about listening (necessarily subjective) when the devices don't have any perceptible differences ?
I don't know, but even reputable companies like TOPPING or SMSL offer settings on their DACs to obtain different 'sound signatures,' even though we probably shouldn't hear them since they use the same circuits but with different harmonics that we shouldn't hear ?
Personally, I haven't tested this type of DAC yet, so could anyone who owns one say whether they perceive any differences or not ?
What explanation could these companies provide if, however, differences were indeed audible ?
Are they hiding something new from us in terms of listening that they have discovered and measured (proven) ?
Given what is currently known, I have no personal answer to offer...
Everyone seems to agree that the measurements on current devices are no longer audible.
Can we still talk about listening (necessarily subjective) when the devices don't have any perceptible differences ?
I don't know, but even reputable companies like TOPPING or SMSL offer settings on their DACs to obtain different 'sound signatures,' even though we probably shouldn't hear them since they use the same circuits but with different harmonics that we shouldn't hear ?
Personally, I haven't tested this type of DAC yet, so could anyone who owns one say whether they perceive any differences or not ?
What explanation could these companies provide if, however, differences were indeed audible ?
Are they hiding something new from us in terms of listening that they have discovered and measured (proven) ?
Given what is currently known, I have no personal answer to offer...
Similar threads
- Poll
